Conventional aluminum-lithium alloys often contain copper, magnesium, and may also contain manganese and/or zirconium in some cases. Aluminum alloys containing lithium additions are beneficial because lithium reduces the density of aluminum alloys by about three percent and increases the modulus of elasticity by about five percent for every weight percent of lithium added. However, the addition of lithium to aluminum alloys may also result in a decrease in ductility and fracture toughness. For use in aircraft parts and aerospace components an alloy should have excellent fracture toughness and strength properties, but it will be appreciated that both high-strength and high-fracture toughness are difficult to obtain in conventional alloys. Furthermore, in order for lithium-containing aluminum alloys to be selected for aerospace or aircraft components, their performance must reach that of alloys commonly used, particularly in the compromise between static mechanical strength and damage tolerance, which are generally antinomic. Said alloys must also have good corrosion resistance. It will be appreciated that the alloys must also be processed in a manner to adequately control the balance of strength, toughness, corrosion resistance, and density.
Materials cost is a major concern in the aerospace industry. One method to reduce the cost of extruded aluminum alloy products is to cut down on the raw material cost. The addition of silver, especially in the presence of magnesium, has proven beneficial in aluminum-copper-lithium alloys. For example, silver is intentionally added to registered aluminum-copper-lithium alloys AA2050, AA2055, AA2075, AA2085, AA2094, AA2095, AA2195, AA2295, AA2395, AA2196, AA2296, AA2098, and AA2198, but silver additions can add significant raw materials costs to a product. Therefore, a more desirable alloy would be essentially silver-free with silver only being an impurity. It will be appreciated that a silver-free aluminum-copper-lithium alloy that still maintains high strength levels, high fracture toughness, and low density would be a desirable aluminum-copper-lithium product.